Conventionally, a refrigerant circuit such as in an air conditioner includes various control valves including a solenoid valve for shutting off the flow of refrigerant and a check valve for permitting the flow of refrigerant only in a single direction. For example, an air conditioner disclosed in Patent Document 1 includes an outdoor unit and a plurality of indoor units. Between the outdoor unit and each of the indoor units is connected a BS unit as an intermediate unit for switching between refrigerant flow paths.
The BS unit has a refrigerant pipe structure in which a plurality of on-off valves and the like are provided. The BS unit is configured to be switchable, with the switching of each on-off valve, between a state in which refrigerant evaporated in the associated indoor unit flows into the BS unit and flows out towards a compressor in the outdoor unit, and a state in which refrigerant discharged from the compressor in the outdoor unit flows into the BS unit and flows out towards the associated indoor unit. Thus, the indoor units can be individually switched between cooling and heating operations.
Patent Document 1: Published Japanese Patent Application No. H11-241844